The development of a microfluidic device, in which various kinds of fluids are analyzed and tested or reacted with each other by using fine flow channels in the scale of nanometers to micrometers, has been proceeding.
As a manufacturing method of such a microfluidic device, a method of fabricating it by sticking two substrates in which concave grooves for flow channels are formed in advance has been generally known.
In the technique disclosed in International Patent Publication WO2008/087800, respective joint surfaces of two resin substrates, at least one of which has a groove for a flow channel formed therein, are activated by plasma irradiation or ion beam irradiation, and then the substrates are joined together while applying pressure thereto.
In the technique disclosed in Japanese Patent Application Laid-Open Publication No. 2012-223858, after at least one of two substrates, at least one of which has a groove for a flow channel formed therein, is irradiated with ultraviolet light so as to activate a joint surface thereof, the substrates are joined together while applying pressure thereto, and the substrates are further heated after releasing the pressure.